Supported XPath Expressions

Here are some samples of XPath use in Hpricot:

 require 'hpricot'
 require 'open-uri'
 doc = Hpricot(URI.parse("http://google.com/").read)

 doc.search("/html/body//p")
 doc.search("//p")
 doc.search("//p/a")
 doc.search("//a[@src]")
 doc.search("//a[@src='google.com']")

Location Paths

Absolute Paths

 doc.search("/html/body//p")
 doc.search("/*/body//p")
 doc.search("//p/../div")

Relative Paths

 doc.search("a",this)
 doc.search("p/a",this)

Supported Axes

descendant

Element has a descendant element.

 doc.search("//div/descendant::p")

Identical to doc.search("//div//p") .

child

Element has a child element.

 doc.search("//div/child::p")

Which is identical to: doc.search("//div/p") .

preceding-sibling

Element has an element before it, on the same axes.

 doc.search("//div/preceding-sibling::form")

parent

Selects the parent element of the element

 doc.search("//div/parent::div")

Which is identical to doc.search("//div/../div") .

self

Selects the element itself.

Supported Predicates

• [@*] Has an attribute
  

  doc.search(“//div[@*]”))

• [foo] Has an attribute of foo
  

  doc.search(“//input[@checked]”))

• [foo=‘test’] Attribute foo is equal to test
  

  doc.search(“//a[@ref=‘nofollow’]”))

• [Nodelist] Element contains a node list, for example:
  

  doc.search(“//div[p]”)
  doc.search(“//div[p/a]”)

Supported Predicates, but differently

• [last()] or [position()=last()] becomes :last
  

  doc.search(“p:last”))

• [0] or [position()=0] becomes :eq(0) or :first
  

  doc.search(“p:first”)
  doc.search(“p:eq(0)”)

• [position() < 5] becomes :lt(5)
  

  doc.search(“p:lt(5)”))

• [position() > 2] becomes :gt(2)
  

  doc.search(“p:gt(2)”))